Drying apparatus for photographic film



Jan. 21, 1947. F. P. WILLCOX 2,414,502

DRYING APPARATUS FOR PHOTOGRAPHIC FILM Filed Sept. 13, 1944 3Sheets-Sheet 1 I $1 vwento'o Frederick F6021 ZZcox Jan. 21, 1947. w cox2,414,502

DRYING APPARATUS FOR PHOTOGRAPHIE FILM Filed Sept. 13, 1944 3Sheets-Sheet 2 7 nvzntoz i Frederic/c BZUL'ZZCOX Jan. 21, 1947. vWILLCQX 2,414,502

DRYING APPARATUS FOR PHOTOGRAPHIC FILM Filed Sept. 15, 1944 -3Sheets-Sheet 3 uuenfo'o Frederick Z. LUL'ZZCOX a 21 a, a

SHGZHQIJ4 Patented 21, 1947 2,414,502 DRYING APPARATUS FOR PHOTOGRAPHICFrederick P. Willcox,

Arlingto United States Army, :1, Va.

Application September 13, 1944, Serial No. 553,855

(01. 34-197) (Granted under the act of March 3, 1883, as

8 Claims.

amended April 30, 1928; 370

The invention described herein may be manufactured and used by or forthe Government for governmental purposes, without payment to me of anyroyalty thereon.

This invention relates to a photographic film drying cabinet,particularly a photographic film drying cabinet in combination with animpeller directing a current of air through the cabinet, and moreparticularly it is directed to a photographic film drying cabinet incombination with an impeller and efllcient heating assembly fordirecting a current of heated air through the cabinet.

In the past, it has been the practice in the design of equipment of thistype to locate an air inlet near the bottom of the cabinet and an exitflue near the top. Various means for heating the air have evolved in theadvancement of this art, !or instance combustion gases, heat exchangecoils, and electrical elements have been used. The circulation or airthrough the cabinet has likewise varied, some devices relying on thevariance of air densities while others provided impelling and exhaustingdevices. In all cases, however, the devices were unsatisfactory for manyreasons such as contaminating the air, and requiring a large poweroutput to secure an adequate rise in temperature of the air circulatedover film supported in the cabinet.

Accordingly, it is an object of this invention to provide a photographicfilm drying cabinet having an air impeller circulating air therethroughand an efilcient electrical heating assembly for heating the air.

Another object of this invention is to provide a device of the classherein described having the heating element supported by and positionedin air directing vanes forming conduits registering with the air inletfor the impeller.

A further object of this invention is to provide a device of the classherein described which will .be economical and simple to construct andemcient, economical and durable in operation.

The foregoing and other objects of this invention will be more apparentfrom reading the specification in conjunction with the drawings forminga part thereof, wherein:

Fig. 1 is a perspective view of the impeller, directing vanes, and hoodmounted on top of and operably connected with the cabinet;

Fig. 2 is a detailed cross-sectional view showing the construction andarrangement 01 the impeller, directing vanes, and heater element; and,

Fig. 3 is a perspective view showing the structural details the cabinetinterior.

In the drawings wherein like members are given the same referencenumeral, a plurality of radial spaced impeller blades I are rigidlysecured to a rotatably mounted shaft 2 in any suitable manner well knownin the art of turbine propellers. The shaft 2 is attached to and rotatedby the rotor of an electric motor 3. The impeller blades I are encasedin a circular shroud 5, which has a tangential exit conduit 6perpendicular to the longitudinal axis of the blades I. The air inlet isan annular flanged aperture 4 in axial alignment with the impellerblades.

In order to provide definite channels or conduits through which the airmust pass in entering the impeller shroud 5, an outwardly flared,substantially bell-shaped directing vane I is superimposed on and inregistering contact with the annular flanged aperture 4 functioning asan air inlet. This directing vane 1 may be securely fastened to theshroud 5 by any suitable means, such as bolting, strapping, welding, andthe like. This structure defines one substantially conical conduitleading to the air inlet; however, a more eiilcient structure may beobtained by suspending a smaller, similarly designed vane 8 interiorlythe outer vane I and in coaxial alignment therewith. The interior vane 8may be rigidly suspended from the outer vane 'I by a,

plurality of equally spaced bars or straps I0. These coaxial aligned airdirecting vanes I and 8 form two distinct channels leading to the airinlet 4, and each of these channels directs air over a heating elementI5 positioned in the air paths formed by the directing vanes I and 8.Thus, all of the air entering the system is heated by contact with andradiation from the heating element. The air, however, is also heated bythe vanes I and 8 and impeller blades I, which absorb heat radiated fromthe heating element I5. In order to obtain the maximum heating effectfrom the vanes I and 8 and blades I, they should be rendered more heatabsorptive, preferably by coating with a heat absorptive material suchas lusterless black paint.

The supporting bars III, in addition to supporting the inner vane 8,also support, in axial alignment with the impeller blades I and coaxialaligned vanes I and 8, an electrical socket II. The socket II has twoelectric contacts, one at the base of the socket and the other inassociation with an internally threaded section II, as is theconventional practice in this art. A molded ceramic form has a hollowconical shaped portion I4 wound with coiled resistance wire Ii to form aheating element, and a cylindrical shaped portion provided with externalthreads adapted to engage the threaded portion 12 of the socket I I. Theheating element wire I is provided with two electrical contacts, one atthe base of the ceramic form and the other in association with theexternal threads it. The electrical circuit is completed upon engagementof the threaded members.

The cabinet, impeller and heater are so connected as to form a singleclosed conduit, with the air entering the inlet of the directing vanesand leaving through exits provided near the bottom of the cabinetstructure. The air directing, heating, and impelling means, abovedescribed, are mounted on the top of the cabinet structure insuring acleaner air supply. A conduit i'i connects the impeller shroud to apyramidal hood l8 registering with an aperture it! provided in thedrying cabinet top member 20. The air in the upper portion of a room isnormally clean enough for drying film; however, if fine grain work is tobe dried, a filter may be positioned in the hood is or between the hoodl8 and registering aperture l9. The cabinet side members 2| are providedwith a plurality of apertures 22 near the lower edge thereof to serve asexits for the air directed therethrough by a double arcuate directingvane 26 attached to the bottom member 25. The solid back member 23 andinterlocking dual door members 20 complete the cabinet structure forminga part of the conduit.

It is a desirable feature of the cabinet that a portion of the interiorthereof be free of shelvin to accommodate roll or strip fllm and theremaining portion have vertically adjustable shelving to accommodateplates of various sizes. Accordingly, there are provided, in the desiredlength, a plurality of shelves having a width comparable to the depth ofthe cabinet. Each shelf consists of an angle frame 21 with downwardlyextending flanges and a body of heavy wire screen 28 attached to theinwardly extending horizontal flanges of the angle frame 2!. The shelvesare supported at three points by upwardly extending flanges 30 engagingthe downwardly extending flanges of the angle frame 2'8; and, at anotherpoint by a stud 3 attached to the angle frame 21! and inserted in anaperture 53 provided in a vertical supporting member 32. The supportingflanges 30 are stamped in strips 09, in a manner such that they are inspaced relation therewith, and correponding flanges 30 in each strip 3!are in planular alignment. If desired, angle members may be used in lieuof strips 3 i. Two of the flanged strips M are attached to the cabinetback member 23, and another flanged member is secured at the joinder ofthe side member 2i and interlocking door 24. This latter flange memberis preferably stamped in an an le member. These flanged members supportthe shelves at the back and one front corner. The other front corner ofthe shelf is supported by stud 84 attached to the angle frame 21 andinserted through an aperture 33 in a vertical support 32. The supportconsists of an angle member 32 positioned near the front of the cabinetand secured to the top 20 and bottom 25 members .thereof. The elongatedapertures 33 are so spaced that they are in planular alignment with thecorresponding upwardly extending flanges 30. The stud I4 is secured tothe angle frame 21in a position registering with the elongated aperture03. To insert a shelf, it is tilted upwardly at the back, the stud 84inserted through an aperture 33 at the desired height, and the frontdance of the angle frame 21 placed over the corresponding flange 30. The

members 2 I.

rear portion of the shelf is then pushed downwardly until the angleframe 21 engages the flanges 30 provided on the cabinet back member 23.Thus, the shelves are easily adjusted to the desired height toaccommodate articles of various sizes. g

The fabrication and assembly of this device is economical and relativelysimple. conventional, rectangular cabinet structure is provided with anaperture I9 in the top member 20 and'a plurality of apertures 22 in thelower section of the side members 2 I. The double arcuate vane26-iscentrally positioned and fastened tothe cabinet bottom member 25.If it is desired to filter air passing through the cabinet, an airflltermay be positioned over the inlet aperture l9; likewise, a filtercloth may be placed over the exit apertures 22 to prevent the entranceof dust into the cabinet when not in use. The pyramidal hood I8 isconstructed of sheet metal and secured in registering contact with theaperture H9 in the cabinet top member 20. The motor 3 and the blower,which is a standard turbine impeller i coated with black paint andencased in a circular shroud 5 having a tangential exit 6 and side inlet4, are mounted on top of the cabinet and operable connected with thehood 68 by a prefabricated sheet metal conduit H. The directing vanes land 8 are fabricated from sheet metal coated with lusterless blackpaint, and assembled with suspending bars l0 having the electric socketIi secured to them. The ceramic form having the heating element 15 woundthereon is screwed into the socket, and the directing vanes supportingthe heater assembly is secured to the flanged air inlet 5 of the blowerassembly.

In operation, the device is efficient, economical, and durable. Filmplates are supported separately in the cabinet by suspending them fromthe wire structure 28 of a shelf and they are supported collectively byplacing them in a film plate rack resting on the shelf, and roll filmsare suspended in the unshelved portion of the cabinet. When the doors 2dare shut, a closed conduit for the cabinet is formed with the inlet atthe directing vanes l and 8 and outlet at the apertures 22 in the lowersection of the side The motor 3 and heating element is are energizedthereby pulling air through the channels formed by the directing vanes land 8 and over the heating element i5. The directing vanes heat the airwith absorbed heat radiated from the heating element I5, which alsoheats the air by radiation and contact. The air is also heated by theradiated heat absorbed by the impeller blades I which propels it throughthe conduit ll, hood i8, and cabinet where it is directed -by the doublearcuate vane 25 out the apertures 22.

As an example of the increased efflciency ,obtained in the devicedescribed herein, a four inch impeller driven by a /5 H. P. motorproduced an output of approximately 250 cubic feet of air a minute atanincreased temperature of 35 F. in the cabinet above atmospherictemperature with a heater element current consumption of only 660 watts;whereas, a similar structure without directing vanes I and 8 and havingthe heating element disposed across the impeller exit 6 consumed inexcess of 2000 watts to produce the same temperature rise.

Having thus described my invention, what I claim as new and wish tosecure by Letters Patentis:

1. In combination. a cabinet having adjustable A standard,

impeller having an air conduit; and, an electrical heating device cominthe cabinet top member, a conduit operably connected with said hood, andan encased air impeller having an air exit registering with saidconduit; and, an electrical heating device comprising air directingvanes, secured to the inlet of said encased impeller, and an electricalheating element supported by said directing vanes, said combinationbeing constructed and arranged in a manner such thatsaid impeller drawsheated air from said heating device and directs said heated air throughsaid top cabinet aperture thence downwardly through said cabinet overand against said double arcuate air directing vane.

a hood registering with and inserted over said aperture in the cabinettop member,-a conduit operably connected with said hood, and an encasedair impeller having anair exit registering with said conduit; and, anelectrical heating device comprising air directing vanes attached to theinlet of said impeller, and an electrical heating element supportedinteriorly said air directing vane, said combination being constructedand arranged in a manner such that said impeller draws heated air fromsaid heating device and directs said heated air through said top cabinetaperture thence downwardly through said cabinet over and against saiddouble arcuate air directing vane.

3. In combination, a cabinet having adjustable shelves occupying avertical portion thereof, an aperture in the top of said cabinet, aplurality of apertures in the lower portion of the side members of saidcabinet, and a double arcuate air directing vane located interiorly saidcabinet and attached to the bottom member thereof; a hood registeringwith and inserted over said aperture in the cabinet top member, aconduit operably connected with said hood, and an encased air impellerhaving an air exit registering with said conduit; and, an electricalheating device comprising a plurality of air directing vanes coaxiallyaligned with said impeller, and a heating element positioned in axialalignment with said air directing vanes, said combination beingconstructed and arranged in a manner such that said impeller drawsheated air from said heating device and directs said heated air throughsaid top cabinet aperture thence downwardly through said cabinet overand against said double arcuate air directing vane.

4. In combination, a. cabinet having adjustable shelves occupying avertical portion thereof, an aperture in the top of said cabinet, aplurality of apertures in the lower portion of the side members of saidcabinet, and a double arcuate air directing vane located interiorly saidcabinet and attached to the bottom member thereof; a. hood registeringwith and inserted over said aperture in the cabinet top member, aconduit operably connected with said hood, and an encased air prisingcoaxially aligned substantially-bell-shaped air directing vanes attachedto the air inlet or said impeller, and an electrical heating elementposithrough said cabinet over and against said double arcuate airdirecting vane.

5. In combination, a cabinet having adjustable shelves occupying avertical portion thereof, an aperture in the top 01' said cabinet,-aplurality of apertures in the lower portion of the side members of saidcabinet, and a double arcuate air directing vane located interiorly saidcabinet and attached to the bottom member thereof; a hood registeringwith and inserted over said aperture in the cabinet top member, aconduit operably connected with said hood, and an encased air impellerhaving an air exit registering with said conduit; and, an electricalheating device comprising air directingvanes attached to the inlet ofsaid impeller, a heat absorptive coating on said directing vanes, and anelectrical heating element supported by said directing vanes, saidcombination being constructed and arranged in a manner such that saidimpeller draws heated air from said heating device and directs saidheated air through said top cabinet aperture thence downwardly throughsaid cabinet over and against said double arcuate air directing vane.

6. In combination, a cabinet having adjustable shelves occupying avertical portion thereof. an aperture in the top of said cabinet, aplurality of apertures in the lower portion of the side members of saidcabinet, and a double arcuate air directing vane located interiorly saidcabinet and attached to the bottom member thereof; a hood registeringwith and inserted over said aperture in the cabinet top member, aconduit operably connected with said hood, and an encased air impellerhaving an air exit registering with said conduit; and, an electricalheating device comprising air directing vanes attached to the inlet ofsaid impeller, a heat absorptive coating on said directing vanes, and aheating element supported interiorly said directing vanes, saidcombination being constructed and arranged in a manner such that saidimpeller draws heated air from said heating device and directs saidheated air through said top cabinet aperture thence downwardly throughsaid cabinet over and against said double arcuate air directing vane.

7. In combination, a. cabinet having adjustable shelves occupying avertical portion thereof, an aperture in the top of said cabinet, aplurality of apertures in the lower portion of the side members of saidcabinet, and a double arcuate air directing vane located interiorly saidcabinet and attached to the bottom thereof; a hood registering with andinserted over said aperture in the cabinet top member, a conduitoperably connected with said hood, and an encased air impeller having anair exit registering with said conduit; and, an electrical heatingdevice comprising a plurality of air directing vanes coaxially alignedwith said impeller, a heat absorptive coating on said directing vanes,and an electrical heating element positioned in coaxial alignment withsaid directing vanes, said combination being constructed and arranged ina manner such that said impeller exit registering with said draws heatedair from said heating device' and directs said heated air through saidtop cabinet aperture thence downwardly through said cabinet over andagainst said double arcuate air directing vane.

8. In combination, a cabinet having adjustable shelves occupying avertical portion thereof, an aperture in the top or saidcabinet, aplurality of apertures in the lower portion of the side members of saidcabinet, and a double arcuate air directing vane located interiorly saidcabinet and attached to thebottom member thereof a hood registering withand inserted over said aperture in the cabinet top member, a conduitoperably connected with said hood, and an encased air directing vane.

impeller having an air exit registering with said conduit: and. anelectrical heating device comprising coaxially aligned substantiallybell-shaped air directing vanes attached to the inlet of said airimpeller, a heat absorptive coating on said directing vanes, and anelectrical heating element positioned in coaxial alignment with saiddirecting. vanes, said combination being constructed and arranged in amanner such that said impeller draws heated air from said heating deviceand directs said heated air through said top cabinet aperture thencedownwardly through said cabinet over and against said double arcuate airFREDERICK P. WILLCOX.

